Integrating classical methods and a new viability index to assess shallow ground heat exchange potential: application to the Gioia Tauro coastal plain (Calabria, southern Italy)

This study investigates the shallow ground heat exchange capability in the highly industrialized Gioia Tauro Plain (Southern Italy), integrating geological, hydrogeological, thermal, and geochemical data to assess the feasibility of both closed-loop and open-loop systems associated to geothermal heat pumps. For closed-loops the G.POT method was applied, enabling the calculation of extractable thermal energy based on soil properties and climatic conditions. For open-loops a comprehensive analysis was conducted using aquifer transmissivity, hydraulic conductivity, and geochemical features to identify the most suitable sectors. For the latter systems, a newly developed Geothermal Potential Viability Index was also proposed for a simplified system evaluation. Results show that the north-western sector of the plain has the highest suitability for closed-loop installations, due to high thermal conductivity and shallow water table. In contrast, areas near the Mesima and Budello river mouths exhibit physicochemical limitations for open-loop use, such as calcite oversaturation, high salinity, and elevated trace metal concentrations, which may significantly reduce the efficiency of open-loop systems. This integrated assessment provides a robust tool for energy planning, helping to identify high-potential zones while accounting for environmental risks and economic constraints.